(en-sef″ă-lop′ă-thē ) [encephalo- + -pathy] Generalized brain dysfunction marked by varying degrees of impairment of speech, cognition, orientation, and arousal. In mild instances, brain dysfunction may be evident only during specialized neuropsychiatric testing. In severe instances, e.g., the last stages of hepatic encephalopathy, the patient may be unresponsive even to unpleasant stimuli.